Document
U2400B
Charging of Batteries with Automatic Pre-Discharge
Description
The monolithic integrated circuit, U2400B, is a bipolar circuit, designed for automatic recharging of NiCd/ NiMH batteries. It has controlled and defined charging
characteristics for various charging sequences with
*subsequent trickle charge operation. The long life *Memory Effect of the recharging cell remains intact.
Features
D Three time selections:
0.5 h, 1 h or 12 h with subsequent trickle charge operation
D Battery temperature and contact monitoring
D Charging interrupt for overvoltage or excessive
temperature
D Automatic pre-discharge possible
D Separate charge- and discharge outputs
D Pulse-width modulation facility of charge- and
discharge current for matching to transformer or battery data
D Timer clock via mains or internal oscillator
D Reference voltage source
D LED-status output for mode indication
Case: DIP16, SO16L
8 14
16 0.5 Hz
94 9375
11 Mains supply 7
Reference
Open Ref on off
Test logic
Mains synchronization
1
3 200 Hz Oscillator
– 2+
Control unit
PWM Time
Status Discharge Reset
13
Ref 12 h GND 1 h
Charge time
selection Open 0.5 h
Failure – charge mode
II Continue Alternating 15 Ref charging red / green
I Stop
Red
Open charging indicator
Status display output
9
Charge Start
Stop
Charge output 12
Discharge stop
0.53 V + –6
0.53 V +
– Sensor monitoring
5
+ – 2.95 V
Event counter
Vmax
0.53 V
–
+4
Battery contact monitoring
– + 0.18 V
10
Discharge output
Figure 1. Block diagram
TELEFUNKEN Semiconductors Rev. A2, 21-Nov-96
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TELEFUNKEN Semiconductors Rev. A1, 21-Nov-96
2 (15)
Figure 2.
220 mF
10 mF
V Ref
430 kW
C1 11
C3 7
R1 3
15 nF
C2
2
B1 13 B2
open
15
+V S 8
Mains supply Reference
14
Open on
Ref off
16 0.5 Hz
Test logic
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Mains synchronization
1
D2 ... D5 BYX86 D1 BYX86
G A1
A2
V = 12 V~
200 Hz Oscillator
Control unit
PWM Time
Status Discharge Reset
Ref GND Open
12 h 1h
0.5 h
Charge time
selection
Failure – charge mode
II Continue Alternating Ref charging red / green
I Stop
Red
Open charging indicator
Status display output
9
Charge Start
Stop
Charge output
12
Discharge stop
0.53 V + –6
0.53 V +
– Sensor monitoring
5
+ – 2.95 V
Event counter
V max
Battery contact monitoring
Discharge output
0.53 V – +4
– + 0.18 V
10
R7
TLHR5400
TLHG5400
R6
330 W
red
green
330 W
R9
220 W WR 5
100 k
0.33 mF
C5
WR3
10 k
R 13
V Ref
WR6 30 k
R 17
1.5 kW
W0.33 mF
R4 100 k
VBattery = 7.2 V
WR2
C4 5.6 k
R 14
1 kW
R 10
10 kW
T1 BD135
R 12
NTC Sensor M 87
WR(25) = 10 k
U2400B
U2400B
General Description, Figures 2 and 3
The integrated circuit, U2400B, supports specially the controlled and defined charging of fast NiCd cells. Varieties of charging time selections, i.e., standard charge (12 h), quick charge (1 h) or fast charge (0.5 h) are possible.
Before the charging begins, cell is discharged completely.
* *In this way, the long life Memory Effect of the
recharging cell remains intact. Surveillance is taken over by control unit for time, thermal and voltage during the charging and switch-off when the specified capacity is attained. When switched on, the red LED connected to the display output (Pin 9) is activated. This is only the case if no battery is connected. When a battery is inserted with a minimum voltage of approximately 180 mV at Pin 4, the pre-discharge phase is then started with a 2 seconds delay. The discharge output at Pin 10 is activated. This is
indicated by the flashing red LED (see figure 5). The discharge procedure is stopped with a voltage less than 530 mV (at Pin 6). The following charge phase (charge output Pin 12 active) is indicated by the flashing green LED (Pin 9).
After the programmed charging period (Pin 13: 0.5 or 1 h continuous charge, or 12 h pulsed charge) the trickle charge phase is reached (figure 4). This trickle charge mode is indicated by the on-state of the green LED. This means, the battery has stored the maximum possible
*amount of energy. The outputs display, discharge and *charge will be set inactive (by temperature, over-
voltage). The timer clock is interrupted during the inactive phase and in each mode when a limit value (Pins 4 and 5) is exceeded.
START Reset
no Pin 9: “0”
Battery inserted ?
yes
Pin 9: “open”
Pin 9: Alternating blinking yes
Pin 15 = VRef no
Pin 9: “0”
Trickle charge Pin 12: “0” pulsed Pin 10: open
Pin 9: “1”
yes no Time
t > tmax ?
yes
no Event counter Z<2?
V < Vmax ?
no
STAND – BY
Increment event counter Pin 12: open Pin 9: open Pin 10: open
Timer stop
yes
no yes T < Tmax ?
Discharge
Pin12: open Pin 9: “0” pulsed Pin 10 “1”
Timer stop
no
“Discharged” memory set ?
no
yes
Charge
Pin 12: “1” pulsed Pin 9: “1” pulsed Pin 10: open
Timer run
Figure 3. Flow chart
V < Vmin ?
yes
Set “discharged” memory
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TELEFUNKEN Semiconductors Rev. A2, 21-Nov-96
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U2400B
A two-stage event counter will be incremented with each limit value violation. If the .